1DBCOL(1) User Contributed Perl Documentation DBCOL(1)
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6 dbcol - select columns from an Fsdb file
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9 dbcol [-v] [-e -] [column...]
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12 Select one or more columns from the input database. If a value is
13 given for empty columns with the -e option, then any named columns
14 which don't exist will be created. Otherwise, non-existent columns are
15 an error.
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17 Note: a safer way to create columns is dbcolcreate.
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20 -r or --relaxed-errors
21 Relaxed error checking: ignore columns that aren't there.
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23 -v or --invert-match
24 Output all columns except those listed (like grep -v).
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26 -a or --all
27 Output all columns, in addition to those listed. (Thus "-a foo"
28 will move column foo to the first column.)
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30 -e EmptyValue or --empty
31 Specify the value newly created columns get.
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33 --saveoutput $OUT_REF
34 Save output writer (for integration with other fsdb filters).
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36 and the standard fsdb options:
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38 -d Enable debugging output.
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40 -i or --input InputSource
41 Read from InputSource, typically a file, or - for standard input,
42 or (if in Perl) a IO::Handle, Fsdb::IO or Fsdb::BoundedQueue
43 objects.
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45 -o or --output OutputDestination
46 Write to OutputDestination, typically a file, or - for standard
47 output, or (if in Perl) a IO::Handle, Fsdb::IO or
48 Fsdb::BoundedQueue objects.
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50 --autorun or --noautorun
51 By default, programs process automatically, but Fsdb::Filter
52 objects in Perl do not run until you invoke the run() method. The
53 "--(no)autorun" option controls that behavior within Perl.
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55 --header H
56 Use H as the full Fsdb header, rather than reading a header from
57 then input.
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59 --help
60 Show help.
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62 --man
63 Show full manual.
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66 Input:
67 #fsdb account passwd uid gid fullname homedir shell
68 johnh * 2274 134 John_Heidemann /home/johnh /bin/bash
69 greg * 2275 134 Greg_Johnson /home/greg /bin/bash
70 root * 0 0 Root /root /bin/bash
71 # this is a simple database
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73 Command:
74 cat DATA/passwd.fsdb account | dbcol account
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76 Output:
77 #fsdb account
78 johnh
79 greg
80 root
81 # this is a simple database
82 # | dbcol account
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85 dbcolcreate(1), Fsdb(3)
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88 Copyright (C) 1991-2022 by John Heidemann <johnh@isi.edu>
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90 This program is distributed under terms of the GNU general public
91 license, version 2. See the file COPYING with the distribution for
92 details.
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96perl v5.34.1 2022-04-04 DBCOL(1)